A compound represented by formula (I): ##STR1## wherein R.sup.1 is an organic residue through a carbon atom, R.sup.2 is a carboxyl group which may be esterified or amidated, and X is an oxygen atom, or a sulfur atom which may be oxidized, or a salt thereof, which is useful as antibacterial agent or intermediate for synthesizing the same, and a process for preparing the same.
一种由
化学式(I)表示的化合物:##STR1## 其中R.sup.1是通过碳原子连接的有机残基,R.sup.2是一个可以酯化或酰胺化的羧基,X是一个氧原子,或者一个可以氧化的
硫原子,或其盐,用作抗菌剂或用于合成相同的中间体,以及制备该化合物的方法。